TE 291 
.07 

Copy 1 


JH 


SEVENTH EDITION 


CONCRETE 

SIDEWALKS 

With Chapters on 
CURBS, 

GUTTERS, 

FLOORS and 
PAVEMENTS 


A Book of Practical information 

- for the - 

General Concrete Contractor 


PRICE 35c 


CONCRETE PUBLISHING COMPANY 

Publishers of the Monthly Magazine 
"CONCRETE" 

DETROIT, MICHIGAN 


J] 



























Quality, Quantity and Cost of Output 
Determine the Value of a Mixer 



<1 The capacity of a concrete mixer is a question of vital import¬ 
ance, because the amount of good work the machine will turn out 
continuously practically determines the cost of the job, or the 
amount of profit made. 

<1 The Chicago Improved Cube Mixer, on account of the cube prin¬ 
ciple of mixing, mixes concrete better , and because of its continu¬ 
ous operation will mix it faster than any other machine built. 

•I The Chicago Improved Cube Mixer has no buckets or paddles. 
The batch of concrete is handled as a unit, shifted six times in 
each revolution of the cube, and given a criss-cross motion. This 
produces a perfectly uniform mixture. 

<| There is absolutely no other known way to get the best concrete, 
many claims to the contrary notwithstanding. 

We make fourteen sizes and can furnish an 
outfit for any job of concreting. 

Write for Catalog' No. 27. 

Municipal Engineering and Contracting Company 

RAILWAY EXCHANGE, CHICAGO, ILL. 


30 CHURCH STREET 
NEW YORK 


Agents wanted in unoccupied 
territory 




















* 




























. 






* 





















/ 













































































« 
































. 





Concrete Sidewalks 


□ □ 

Suggestions for Practical and Profitable 
Sidewalk Work 

Standard Specifications 
Curb and Gutter, 

Floors, Driveways, Pavements 


□ 

Compiled by CONCRETE PUBLISHING CO. 
'DETROIT, MICHIGAN 

□ 


Seventh Edition—Revised and Enlarged 

PRICE 35 CENTS 

Copyright, 1911, l)) Concrete Publishing Co. 


CONCRETE SIDEWALKS 



.4 


preface 


About three years ago, the Editors of Concrete put into 
short, concise form the best obtainable information dealing 
with the construction of concrete sidewalks. The first 
edition was printed in the fall of 1907 and rapidly 
exhausted. Reprinted editions were published in January, 
July and December of 1908, and an unusually large edition 
was issued in February, 1909. This also was exhausted 
and a still larger edition was prepared July 15, 1909. This, 
too, has been exhausted and the present edition is made 
necessary. 

All the information that has proved of value in the six 
editions already issued has been retained and a consider¬ 
able amount of new material is printed here. We take 
this opportunity to thank our many friends, who have 
made the preparation of the seventh edition a compara¬ 
tively easy matter. Criticisms and suggestions are always 
welcome in connection with any book we publish. 

Detroit, Michigan, June 10, 1911. 



©CU292267 


CONCRETE SIDEWALKS 


CONCRETE SIDEWALK CONSTRUC¬ 
TION. 

Notwithstanding the extremely wide¬ 
spread use of concrete sidewalks and the 
many capable men engaged in building 
them or in directing their construction, poor 
walks are still occasionally seen. A few 
years ago a concrete sidewalk was a novelty; 
today, any other kind of sidewalk is so novel 
as to be almost unheard of. Cities, towns, 
villages and hamlets are provided with con¬ 
crete. walks, since continued experience has 
shown them to be the best adapted for foot¬ 
ways. Wooden walks are out of the question, 
and, indeed, are prohibited in many cities^ 
Brick walks, owing to the small size of the 
unit employed, seldom remain sightly very 
long; stone walks do not stand traffic so well 
as concrete. Concrete walks have secured 
an unassailable place and when properly laid 
are ideal. 

Durability is, of course, essential in side¬ 
walk construction, if the work is to be econ¬ 
omical. Like almost every other good quality 
in concrete, durability depends entirely upon 
consideration of apparently small details. 
Specifications, the result of concerted reports 
from every part of the country, have been 
prepared for the construction of sidewalks, 


3 


CONCRETE SIDEWALKS 

covering every step in the process. A typical 
set of specifications is the result of work 
done by the National Association of Cement 
Users/ The most recent provisions for work 
of this kind are as follows: 

Materials. 

Cement shall meet the requirements of the 
Standard specifications for Portland Cement 
of the American Society for Testing Mate¬ 
rials, adopted by this Association (January, 
1906). 

Aggregates. 

Fine aggregates shall consist of sand, 
crushed stone or gravel screenings, graded 
from fine to coarse, passing when dry a 
screen having J" diameter holes, shall prefer¬ 
ably be of siliceous materials, clean, coarse, 
free from loam, vegetable or other deleteri¬ 
ous matter, and not more than 3 per cent 
shall pass a sieve having 100 meshes per 
linear inch. 

Mortars composed of 1 part Portland ce¬ 
ment and 3 parts fine aggregate by weight 
when made into briquettes shall show a ten¬ 
sile strength of at least 70 per cent of the 
strength of 1 : 3 mortar of the same consis¬ 
tency made with the same cement and stand¬ 
ard Ottawa sand. 

Coarse aggregate shall consist of inert 
material, graded in size, such as crushed 
stone or gravel, which is retained on a screen 


4 


CONCRETE SIDEWALKS 


having diameter holes, shall be clean, 
hard, durable and free from all deleterious 
materials. Aggregates containing soft, flat 
or elongated particles shall be excluded. 

Maximum size of the coarse aggregate 
shall be such that it will not separate from 
the mortar in laying and will not prevent the 
concrete fully filling all parts of the forms. 
The size of the coarse aggregate shall be 
such as to pass a 1J" ring. 

Natural deposits of sand and gravel, usu¬ 
ally being out of balance, shall be screened 
and remixed to agree with the proportions 
specified under Base. (Below.) 

Where sub-base is specified, only clean, 
hard, suitable materials shall be used, not 
exceeding 4" in the largest dimension. 

Water shall be clean, free from oil, acid, 
strong alkalies or vegetable matter. 

Sub-Grade.* 

Sub-grade shall have a slope toward the 
curb of not less than per foot. 

All soft or spongy places shall be removed, 
and all depressions filled with suitable ma¬ 
terial, which shall be thoroughly compacted 
by flooding and tamping in layers not ex¬ 
ceeding 6" in thickness. 

When a fill exceeding Y in thickness is 
required to bring the walk to grade, it shall 

(a) *Sub-grade shall not be less than 12" below the fin* 
ished surface of the walk. 

(b) Sub-grade shall not be less than 4" below the fin¬ 
ished surface of the walk. 


5 



CONCRETE SIDEWALKS 


be made in a manner suitable to the engineer. 
The top of all fills shall extend beyond the 
walk on each side at least 1', and the sides 
shall have a slope of at least l\". 

When required, a suitable drainage system 
shall be installed and connected with sewers 
or other drains indicated by the engineer. 

Sub-Base.* 

On the sub-base and at least 2" beyond the 
inner and outer lines of the walk shall be 
spread a suitable material hereinbefore speci¬ 
fied, which shall be rammed thoroughly to 
a surface at least 4" below the final grade of 
the walk. On fills, the sub-base shall extend 
the full width of the fill and the sides shall 
have the same slope as the sides of the fill. 

While compacting the sub-base the ma¬ 
terial shall be kept thoroughly wet and 
shall be in that condition when the concrete 
is deposited. 

*When a sub-base is required, omit paragraph (b) 
above. When sub-base is not required, omit paragraphs 
referring to it. 

Forms. 

Forms shall be free from warp and of suffi- 
cent strength to resist springing out of 
shape. All mortar and dirt shall be removed 
from forms that have been previously used. 

Forms shall be well staked to the estab¬ 
lished lines and grades and their upper edges 
shall have sufficient rise from the curb to 
provide proper drainage, but shall not exceed 


6 



CONCRETE SIDEWALKS 

§" per foot except where such rise parallels 
the length of the walk. 

In every 50 linear feet of walk at least one 

joint shall be provided. Any means which 
will provide this will be accepted. 

All forms shall be thoroughly wetted be¬ 
fore any material is deposited against them. 

Slabs. 

Slabs or independently divided block, 
when not reinforced, shall not have an area 
of more than 36 square feet nor any dimen¬ 
sion greater than 6'. Slabs of more than 36 
square feet shall be reinforced with J" steel 
rods, spaced not more than 9" apart, or with 
smaller rods or fabric of equal strength. 

The thickness of slabs for residence dis¬ 
tricts shall not be less than 4" and for busi¬ 
ness districts not less than 5". 

Base. 

Concrete for the base shall be so propor¬ 
tioned that the cement shall overfill the 
voids in the fine aggregate by at least 5 per 
cent and the mortar shall overfill the voids 
in the coarse aggregate by at least 10 per 
cent. Proportions shall not exceed 1 part of 
cement to 8 parts fine and coarse aggregates. 

When the voids are not determined the 
concrete shall be composed of 1 part cement, 
3 parts fine aggregate and 5 parts coarse 
aggregate. 


7 


CONCRETE SIDEWALKS 


Method of measuring the materials for the 
concrete, including water, shall be one which 
will insure separate uniform proportions at 
all times. A bag of cement (94 pounds) 
shall be considered to have a volume of 1 
cubic foot. 

Ingredients of the concrete shall be thor¬ 
oughly mixed dry, sufficient water added to 
obtain the desired consistency, and the mix¬ 
ing continued until the materials are uni¬ 
formly distributed and the mass is uniform 
in color and homogeneous. 

When the conditions will permit, a ma¬ 
chine mixer of a type which insures the 
uniform proportioning of the materials 
throughout the mass shall be used. 

When it is necessary to mix by hand, mix¬ 
ing shall be done on a water-tight platform 
and the materials shall be turned until they 
are homogeneous in appearance and color. 

The materials shall be mixed wet enough 
to produce a concrete of a consistency that 
will flush readily under light tamping, but 
which can be handled without causing a sep¬ 
aration of the coarse aggregate from the 
mortar. 

Retempering, that is, remixing with addi¬ 
tional water, mortar or concrete that has 
been partially hardened, will not be per¬ 
mitted. 

Forms shall be filled and the concrete 
struck off and tamped down sufficiently to 
receive a top of the required thickness. After 


8 


CONCRETE SIDEWALKS 

the addition of water, the mixture shall be 
handled rapidly to the place of final deposit. 
Under no circumstances shall concrete be 
used that has partially hardened. 

Concrete shall not be mixed or deposited 
when the temperature is below freezing un¬ 
less special precautions are taken to avoid 
the use of materials containing frost, and to 
protect the work against frost until thor¬ 
oughly hardened. 

Workmen shall not be permitted to walk 
on freshly laid concrete, and where sand or 
dust collects on the base it shall be removed 
carefully before the wearing surface is 
applied. 

Wearing Surface. 

Wearing surface'shall be mixed of 1 part 
cement and not more than 2 parts fine aggre¬ 
gate, with sufficient water to produce a con¬ 
sistency which will not require tamping, but 
which can be easily spread into position with 
a straight edge. Mortar for the wearing sur¬ 
face shall be mixed in a mortar box. 

Wearing surface shall be spread on the 
base immediately after mixing, and in no 
case shall more than 50 minutes elapse be¬ 
tween the time the concrete for the base is 
mixed and the wearing surface is placed. 

Wearing surface of a walk in a residence 
district shall be at least §" thick, and in a 
business district at least l" thick. 


9 


CONCRETE SIDEWALKS 

After the wearing surface has been worked 
to an approximately true plane the slab 
markings shall be made. If joints havp been 
provided in the base during construction or 
have been cut in the base prior to spreading 
the wearing surface, the markings shall be 
made with a tool which will cut entirely 
through the surface and completely separate 
the wearing surface of adjacent slabs. If 
joints have not been provided in the base 
they must be made with a tool which will cut 
through to the sub-base and completely sep¬ 
arate adjacent slabs. 

Slabs shall be rounded on all surface edges 
to a radius of about . 

When required, the surface shall be trow¬ 
eled smooth. The application of neat cement 
to the surface in order to hasten the harden¬ 
ing is prohibited. 

On grades exceeding 8 per cent the surface 
shall be roughened. This may be done by 
the use of a groover, toothed roller, brush, 
float or other suitable tool. 

When coloring matter is required it shall 
be mixed dry with the sand and cement, 
which have been previously mixed dry, until 
the mixture is of a uniform color. The quan¬ 
tity and quality of the coloring shall be such 
as not to impair the strength of the wearing 
surface. 

When completed, the walk shall be kept 
moist and protected from traffic and the ele¬ 
ments for at least three days. 


10 


CONCRETE SIDEWALKS 


Single Coat Work. 

With the following exceptions the specifi¬ 
cations covering two-coat work will apply to 
single coat work: 

Proportions shall not exceed 1 part ce¬ 
ment, 2 parts fine aggregate and 3 parts 
coarse aggregate. 

Materials shall be mixed wet enough to 
produce concrete of a consistency which will 
not permit tamping, but which can be han¬ 
dled without causing a separation of the 
coarse aggregate from the mortar. 

Forms shall be filled, the concrete struck 
off and the coarse particles forced with a 
suitable tool to a depth below the surface 
which will permit finishing the walk as speci¬ 
fied for two-coat work. 


11 


CURB AND -GUTTER 


CURB AND GUTTER CONSTRUCTION 

Closely connected with concrete sidewalk 
construction is the matter of providing con¬ 
crete curb and gutter. These have been 
adopted by a number of municipalities, and 
are in many ways to be preferred to the older 
stone curbs. The combination curb and gut¬ 
ter, with either plain or reinforced curb, is 
neat, durable and comparatively inexpensive. 

For curb and gutter construction, the fol¬ 
lowing specifications were recently adopted 
by the National Association of Cement 
Users: 

Materials. 

Cement shall meet the requirements of the 
Standard Specifications for Portland cement 
of the American Society for Testing Mater¬ 
ials, adopted by this Association. 

Fine aggregates shall consist of sand, 
crushed stone or gravel screenings, graded 
from fine to coarse, passing when dry a 
screen having diameter holes, shall be 
preferably of siliceous materials, clean, 
coarse, free from loam, vegetable or other 
deleterious matter, and not more than 3 per 
cent shall pass a sieve having 100 meshes per 
linear inch. 

Mortars composed of one part Portland 
cement and 3 parts fine aggregate by weight 
12 


CURB AND GUTTER 

when made into briquettes shall show a ten¬ 
sile strength of at least 70 per cent of the 
strength of a 1:3 mortar of the same consist¬ 
ency, made with the same cement and stand¬ 
ard Ottawa sand. 

Coarse aggregates shall consist of inert 
materials graded in size, such as crushed 
stone or gravel, which are retained on a 
screen having J" diameter holes, shall be 
clean, hard, durable and free from all dele¬ 
terious matters. Aggregate containing soft, 
flat or elongated particles shall be excluded. 

The maximum size of the coarse aggre¬ 
gates shall be such that they will not separate 
from the mortar in laying and will not pre¬ 
vent the concrete from filling all parts of the 
forms. The size of the coarse aggregate 
shall be such as to pass a 1J" ring. 

Natural deposits of sand and gravel usual¬ 
ly being out of balance, shall be screened and 
remixed to agree with the proportions speci¬ 
fied under Base. (See Concrete Roadways 
and Street Specifications.) 

Only clean, hard, suitable material shall be 
used, not exceeding 4" in the largest dimen¬ 
sion. 

Water shall be clean, free from oil, acid, 
strong alkalies or vegetable matter. 

The expansion joint filler shall be suitable 
elastic waterproof compound that will not 
become soft and run out in hot weather or 
become hard and brittle and chip out in cold 
weather. 


13 


CURB AND GUTTER 


Sub-Grade. 

When a sub-base is required the sub-grade 
shall be not less than 12" below the finished 
surface of the gutter. 

All soft or spongy places shall be removed 
and all depressions filled with suitable filling 
material, which shall be thoroughly com¬ 
pacted by flooding and tamping in layers not 
exceeding 6" in thickness. 

When a fill exceeding Y in thickness is re¬ 
quired to bring the work to grade it shall be 
made in a manner satisfactory to the engi¬ 
neer. 

When required, a suitable drainage system 
shall be installed and connected with sewers 
or other drains indicated by the engineer. 

Sub-Base. 

A sub-base shall be provided if required by 
the engineer, composed of cinders or other 
suitable material hereinbefore specified, 
which shall be rammed thoroughly to a sur¬ 
face at least 6" below the finished surface of 
the gutter. 

While compacting the sub-base the mater¬ 
ial shall be kept thoroughly wet and shall be 
in that condition when the concrete is de¬ 
posited. 

Forms. 

Forms shall be free from warp, and of 
sufficient strength to resist springing out of 
shape. All mortar and dirt shall be removed 
14 


CURB AND GUTTER 


from forms that have been previously used. 

Forms shall be well staked or otherwise 
held to the established line and grade, and 
their upper surfaces shall conform with fin¬ 
ished surfaces of the curb and the gutter, 
respectively. 

At least once in every 150', expansion 
joints shall be provided. 

All forms shall be thoroughly wetted be¬ 
fore any material is deposited against them. 

Completed curb must be at least 24" deep, 
not less than 12" thick at the base, not less 
than 6" thick at the top, and the street side 
shall have a batter of 1 to 4. 

For combination curb and gutter, the 
curb must be at least 12" deep at the back 
and the depth of the face not less than 6". 

Breadth of the gutter shall not be less than 
16" nor more than 24". 

Construction. 

Curb and gutter shall be divided into sec¬ 
tions not less than 5' nor more than 8' long, 
by some method which will insure the com¬ 
plete separation of the sections by a joint not 
less than J" nor more than J" wide. 

Concrete. 

The concrete for the curb and gutter shall 
be so proportioned that the cement shall 
overfill the voids in the fine aggregate by at 
least 5 per cent., and the mortar shall overfill 
15 


CURB AND GUTTER 

the voids in the coarse aggregate by at least 
10 per cent. The proportions shall not ex¬ 
ceed 1 part cement to 8 parts fine and coarse 
aggregates. When the voids are not deter¬ 
mined, the concrete shall be composed of 1 
part cement, 3 parts fine aggregate and 5 
parts coarse aggregate. 

The method of measuring the materials 
for the concrete, including water, shall be 
one which will insure separate uniform pro¬ 
portioning at all times. A bag of cement (94 
pounds) shall be considered to have a vol¬ 
ume of 1 cubic foot. 

Ingredients of the concrete shall be thor¬ 
oughly mixed dry, sufficient water added to 
obtain the desired consistency, and the mix¬ 
ing continued until the materials are uni¬ 
formly distributed and the mass is uniform 
in color and homogenous. 

When conditions will permit, a machine 
mixer of a type which insures the uniform 
proportioning of the materials throughout 
the mass shall be used. 

When it is necessary to mix by hand, mix¬ 
ing shall be done on a water-tight platform 
and the materials shall be turned until they 
are homogenous in appearance and color. 

Materials shall be mixed wet enough to 
produce a concrete of such a consistency that 
it will flush readily under light tamping and 
which can be handled without causing a sep¬ 
aration of the coarse aggregate from the 
mortar. 

16 


CURB AND GUTTER 


Retempering, that is, mixing with addi¬ 
tional water, mortar or concrete that has 
partially hardened will not be permitted. 

A layer of concrete shall be deposited to 
the top of the gutter form and tamped, the 
width of the gutter, to a surface all points of 
which shall be at least the thickness of the 
wearing surface below the finished surface 
of the gutter. Concrete placed for the curb 
shall be tamped and the remainder of the 
concrete placed and tamped to permit of the 
application of the required wearing surface 
to the face and top of the curb. After the 
addition of water the mixture shall be han¬ 
dled rapidly to the place of final deposit. 
Under no circumstances shall concrete be 
used that has partially hardened. 

Concrete shall not be mixed or deposited 
when the temperature is below freezing un¬ 
less special precautions are taken to avoid 
the use of materials containing frost until 
thoroughly hardened. 

Workmen shall not be permitted to walk 
on freshly laid concrete, and where sand or 
dust collects on the concrete it shall be care¬ 
fully removed before the wearing surface is 
applied. 

Wearing Surface. 

Wearing surface shall be mixed 1 part 
cement and not more than 2 parts fine aggre¬ 
gate, with sufficient water to produce a con¬ 
sistency which will not require tamping, but 
17 


CURB AND GUTTER 


which can be easily spread into position. 
Mortar for the wearing surface shall be 
mixed in a mortar box. 

Wearing surface shall be placed immedi¬ 
ately after mixing, and in no case shall more 
than 50 minutes elapse between the time the 
concrete is mixed and the time the wearing 
surface is placed. 

Wearing surface on the gutter and on the 
top and face of the curb shall be at least §" 
thick. 

Surface and edges of the curb and gutter 
and joints between sections shall be finished 
in a workmanlike manner. 

Edge of the curb on the street side and the 
intersection of the curb and gutter shall be 
rounded to radius of about 1J", all other 
edges to have a radius of about . 

When required, the surface shall be trow¬ 
eled smooth. The application of neat cement 
to the surface in order to hasten hardening 
is prohibited. 

When coloring matter is required it shall 
be mixed dry with the sand and cement 
which have been mixed dry, until the mix¬ 
ture is of a uniform color. Quantity and 
quality of the coloring shall be such as not 
to impair the strength of the wearing sur¬ 
face. 

Protection. 

When completed, the curb and gutter shall 
be kept moist and protected from traffic for 
at least a week. 


18 


ROADWAYS AND STREETS 


CONCRETE ROADWAYS AND 
STREETS. 

Concrete as a material for surfacing roads 
and streets is being used with increasing 
frequency. Its cheapness and durability 
commend it to the taxpayer and the compar¬ 
ative ease and rapidity with which concrete 
pavements can be laid are additional factors 
in its success. The following Standard Speci¬ 
fications for concrete road and street pave¬ 
ments have been adopted by the National 
Association of Cement Users: 

Materials. 

Cement shall meet the requirements of the 
Standard Specifications for Portland cement 
of the American Society for Testing Mate¬ 
rials, adopted by this Association. 

Fine aggregates shall consist of sand, 
crushed stone or gravel screenings, graded 
from fine to coarse, passing when dry a 
screen having ' diameter holes, shall be 
preferably of siliceous materials, clean, 
coarse, free from loam, vegetable or other 
deleterious matter, and not more than 3 per 
cent shall pass a sieve having 100 meshes per 
linear inch. 


19 


ROADWAYS AND STREETS 

Mortars composed of 1 part Portland ce¬ 
ment and 3 parts fine aggregate by weight 
when made into briquettes shall show a ten¬ 
sile strength of at least 70 per cent of the 
strength of a 1:3 mortar of the same con¬ 
sistency, made with the same cement and 
standard Ottawa sand. 

Coarse aggregates shall consist of inert 
material, graded in size, such as crushed 
stone or gravel, which is retained on a screen 
having J" diameter holes, shall be clean, 
hard, durable and free from all deleterious 
matter. Aggregates containing soft, flat or 
elongated particles shall be excluded. 

The maximum size of the coarse aggregate 
shall be such that it will not separate from 
the mortar in laying and the size of the 
coarse aggregate shall be such as to pass a 
14 " ring. 

Natural deposits of sand and gravel usu¬ 
ally being out of balance, shall be screened 
and remixed to agree with the proportions 
specified under Base. 

Only clean, hard, suitable material shall be 
used, not exceeding 4" in the largest dimen¬ 
sion. 

Water shall be clean, free from oil, acid, 
strong alkalies or vegetable matter. 

Expansion joint filler shall be a suitable 
elastic, waterproof compound that will not 
become soft and run out in hot weather or 
become hard and brittle and chip out in cold 
weather. 


20 


ROADWAYS AND STREETS 

Sub-Grade. 

Sub-grade shall have a rise at the center 
of not more than one one-hundredth (1/100) 
of the width of the pavement. 

(a) * Sub-grade shall not be less than 13J" 
below the finished surface of the pavement. 

(b) Sub-grade shall not be less than 7\" 
below the finished surface of the pavement. 

All soft or spongy places shall be removed, 
and all depressions filled with a suitable ma¬ 
terial, which shall be thoroughly compacted 
in layers not exceeding 6" in thickness. 

When a fill exceeding V in thickness is 
required to bring the pavement to grade, it 
shall be made in a manner satisfactory to the 
engineer. 

When required, a suitable drainage sys¬ 
tem shall be installed and connected with 
sewers or other drains indicated by the 
engineer. 

Sub-Base.* 

On the sub-grade shall be spread a suita¬ 
ble material hereinbefore specified which 
shall be rolled or rammed thoroughly to a 
surface at least 7\" below the finished sur¬ 
face of the pavement. 

While compacting the sub-base, the ma¬ 
terial shall be kept thoroughly wet and shall 
he in that condition when the concrete is 
deposited. 

*When a sub-base is required eliminate paragraph b. 

When a sub-base is not required eliminate paragraph a. 

Unless a is eliminated b is void. 

21 



ROADWAYS AND STREETS 

Forms. 

Forms shall be free from warp and of suf¬ 
ficient strength to resist springing out of 
shape. All mortar and dirt shall be removed 
from forms that have been previously used. 

Forms shall be well staked to the estab¬ 
lished lines and grades. 

All forms shall be thoroughly wetted be¬ 
fore any material is deposited against them. 

Expansion Joints. 

Expansion joints wide shall be placed 
at least every 50' and between the curb or 
edge of the gutter and the pavement. 

Base. 

Concrete for the base shall be so propor¬ 
tioned that the cement shall overfill the voids 
at least 5 per cent and the mortar shall over¬ 
fill the voids in the coarser aggregate by at 
least 10 per cent. Proportions shall not 
exceed 1 part of cement to 8 parts fine and 
coarse aggregates. 

When the voids are determined, concrete 
shall have the proportions of 1 part cement, 
3 parts fine aggregate and 5 parts coarse 
aggregate. 

The method of measuring materials for 
the concrete, including water, shall be one 
that will insure separate uniform propor¬ 
tions at all times. A bag of cement (94 

22 


ROADWAYS AND STREETS 

pounds) shall be considered to have a volume 
of 1 cubic foot. 

Ingredients of the concrete shall be thor¬ 
oughly mixed dry, sufficient water added to 
obtain the desired consistency, and the mix¬ 
ing continued until the materials are uni¬ 
formly distributed and the mass is uniform 
in color and homogeneous. 

When conditions will permit, a machine 
mixer of a type which insures the uniform 
proportioning of the materials throughout 
the mass shall be used. 

When it is necessary to mix by hand, mix¬ 
ing shall be done on a water-tight platform 
and the materials shall be turned until they 
are homogeneous in appearance and color. 

Materials shall be mixed wet enough to 
produce concrete of a consistency that will 
flush readily under light tamping, but which 
can be handled without causing a separation 
of the coarse aggregate from the mortar and 
which will not creep towards the curb nor 
sag out of place when deposited and lightly 
tamped. 

Retempering, that is, remixing with addi¬ 
tional water, mortar or concrete that has 
partially hardened, will not be permitted. 

Concrete shall be deposited in strips ex¬ 
tending across the whole area to be paved. 
After the addition of water the mixture shall 
be handled rapidly to the place of final de¬ 
posit. Under no circumstances shall concrete 
be used that has partly hardened. 


23 


ROADWAYS AND STREETS 

Concrete shall not be mixed or deposited 
when the temperature is below freezing un¬ 
less special precautions are taken to avoid 
the use of materials containing frosty and to 
protect the work against frost until thor¬ 
oughly hardened. . 

Workmen shall not be permitted to walk 
on freshly laid concrete, and where sand and 
dust collect on the base they shall be removed 
carefully before, the wearing surface is 
applied. 

Wearing Surface. 

Wearing surface shall be mixed of 1 part 
cement and not more than 1J parts fine ag¬ 
gregate, with sufficient water to produce a 
consistency which will not require tamping, 
but which can be easily spread into position 
with a straight edge. 

Wearing surface shall be spread on the 
base immediately after mixing and in no case 
shall more than 50 minutes elapse between 
the time that the concrete for the base is 
mixed and the time the wearing course is 
floated. 

Wearing-surface of the pavement in a resi¬ 
dence district shall be at least thick, and 
in a business district at least 2" thick. 

Wearing surface shall be finished with a 
wood float, and before it has completely 
hardened it shall be roughened by brushing 
with a stiff vegetable fiber brush or broom. 


24 


ROADWAYS AND STREETS 

Edges of all expansion joints shall be 
rounded to a radius of about 

Where coloring matter is required it shall 
be mixed dry with the sand and cement, 
which have been previously mixed dry, until 
the mixture is of a uniform color. The quan¬ 
tity and quality of the coloring shall be such 
as not to impair the strength of the wearing 
surface. 

Protection. 

When complete the pavement shall be kept 
well sprinkled with water for a period of at 
least three days and shall not be thrown open 
to traffic until the engineer so directs. 


25 


CONCRETE PAVEMENT 


TYPES OF CONCRETE PAVEMENT IN 
GENERAL USE. 

The ideal pavement has been defined as 
one that is durable, clean, sanitary, noiseless, 
easy on traffic, low in price and free from 
excessive maintenance charges. Under prop¬ 
er conditions, concrete paving approaches 
very closely these specifications. In proper 
concrete pavements, the surface is easily 
cleaned and certainly sanitary. It is less 
noisy than stone, brick or asphalt (in cold 
weather), and little more noisy than block, 
while it is of course infinitely longer-lived. 
Teamsters’ unions have generally testified 
that concrete is not hard on the hoofs of 
horses. Its resistance to automobile traffic is 
good, and this is an important point nowa¬ 
days. The surface is readily roughened to a 
point that insures freedom from slipping. 

Concrete pavement is by no means an ex¬ 
periment. Those at Bellefontaine, Ohio, have 
been down seventeen years; Richmond, Ind., 
has been using concrete pavements for thir¬ 
teen. Pavements of these ages in those two 
towns are in first-class condition today. 
They have stood the traffic as well as any 
other form of pavement, and better than 
most other forms. City engineers in Phila¬ 
delphia, Pa., Troy, N. Y., Worcester and 


26 


CONCRETE PAVEMENT 

Lowell, Mass., Davenport, la., Fond du Lac, 
Wis., Washington, D. C., New Orleans, La., 
Denver, Col., Omaha, Neb., and Toronto, 
Ont., speak highly of concrete, after observa¬ 
tion of its advantages as a pavement, extend¬ 
ing over considerable periods. The traffic of 
the largest cities is handled with as good re¬ 
sults as is that of the smaller ones. 

Specifications for the Bellefontaine, Ohio, 
pavement, probably the oldest successful 
pavement of its kind in this country, were 
about as follows: The whole pavement is 6" 
thick, with a concrete base 4" thick and a top 
or wearing surface 2" in thickness. The base 
is 1:4 gravel concrete and the top surface 1 :1 
screened black sand. Concrete was mixed 
in careful proportions, using the continuous 
type of concrete mixer. Cement and aggre¬ 
gate were first measured and mixed and then 
supplied to the mixer proper. Starting at 
either curb, concrete was laid in strips 5' 
concrete pavement in the center, from 10' to 
wide, extending the width of the street, and 
this strip was afterwards blocked off into 
slabs 5' square, care being had to insure com¬ 
plete separation of one block from another. 
No expansion joints, in the ordinary sense 
of the term, were used, the block divisions 
taking their place with entire satisfaction. 
Footing for horses was secured by dividing 
the slabs into blocks about 4" square, using a 
V-shaped tool, about wide and deep on 
the cut. 


27 


CONCRETE PAVEMENT 


, In Mason City, la., the pavement consists 
of 7" of concrete—a base 5" thick, made of 
1:2:5 concrete. Screened stone, from \" to 
\\" in diameter, was used for the coarsest 
aggregate. The top surface was of course 
2" thick. Corrugations were used in the first 
pavement laid, but the engineer in charge 
has decided that in future the pavement will 
be simply roughened with a paver’s broom, 
to give the requisite foot-hold for horses. 
Expansion joints are provided, 1" wide, 
along either curb, and transversely across 
the pavement every 25'. Between these 
joints, or 12' 6" from the transverse expan¬ 
sion joint, there are provided additional 
joints y' wide. A cut down the center of the 
pavement, parallel to the curb, is also pro¬ 
vided. The effect is to block the pavement 
off into slabs about 10' or 12' 6" square, de¬ 
pending a little on the width of the pave¬ 
ment. Expansion joints are filled with as¬ 
phaltic material and their edges treated with 
a rounding tool before the concrete has 
hardened. The absence of sharp edges to 
chip off has resulted satisfactorily. 

This pavement cost $1.25 per square yard, 
including a 7" excavation. Prices of mater¬ 
ial were as follows: Crushed rock, on the 
job, $1.35; sand, on the job, 85c per cubic 
yard; cement, on the job, $1.20 per bbl. La¬ 
bor could be obtained at from $2.00 to $2.50 
per day. Unquestionably these prices are 


28 


CONCRETE PAVEMENT 

lower than would obtain in some other locali¬ 
ties. 

In general, pavements are laid with an 
average thickness of 7"—about 5" for the 
foundation course and about 2" for the top 
or wearing surface. Foundation course is 
mixed about 1 \2\ :4J, and the wearing sur¬ 
face 1:1|. Proper allowance for expansion is 
absolutely essential. 

Materials must be selected with great care. 
Portland cement should be of standard qual¬ 
ity and subjected to all the tests. For aggre¬ 
gate, the hardest stone, like flint, granite or 
trap-rock, should be utilized. 

General Paving Specifications. 

Experience suggests the following general 
specifications: 

The sub-grade shall be the exact shape of 
the finished road, heavily rolled with a 10-ton 
roller, and made absolutely solid. 

In loose, porous soils, no provision for 
drainage is necessary. In heavy or wet soils, 
a layer of cinders or agricultural tile at either 
side of the roadway, in a cinder-covered 
trench, should be provided. 

Sand for the wearing surface should be 
washed and screened, and should consist 
chiefly of siliceous material. 

The hardest stones should be used for the 
coarse aggregate. Crusher-run stone should 
not be utilized, unless all fine material is re¬ 
jected. 


29 


CONCRETE PAVEMENT 

Water should be fresh and free from any 
impurity that will injure concrete. 

Portland cement that is up to the standard 
.specifications of the American Society for 
Testing Materials should be employed. 

Bottom or foundation course should be 5" 
in thickness after complete tamping or roll¬ 
ing. It should consist of 1:2J:5 concrete. 

Wearing surface should be placed immedi¬ 
ately on the foundation course, before the 
latter has had time to set. It should be about 
in thickness, composed of 1 part Port¬ 
land cement and 2 parts selected torpedo 
sand, or 1 of cement, 1 of torpedo sand and 1 
of granite screenings. 

Base should not be mixed too wet. As 
soon as 25' of base are completed, the wear¬ 
ing surface should be put on, using a wet 
mixture, similar to that used for concrete 
sidewalks. 

Work is facilitated by the use of templates, 
drawn to the exact shape of the finished pav¬ 
ing. 

Corrugations are unnecessary on streets 
with a grade of less than 3 per cent. 

Roughness may be secured by brooming 
the pavement as soon as the wearing surface 
begins to stiffen. 

It is unwise to roughen the surface of the 
pavement immediately adjacent to the curb, 
for a distance of say 2 r , as any roughness here 
will result in obstructing the flow of water to 
the drains. 


30 


CONCRETE PAVEMENT 


Expansion joints should be definite and 
thoroughly made, cutting through the top 
coat and the bottom coat of the pavement, 
down to the excavation. They ought to be 
at least 1" wide next to the curbs and trans¬ 
verse joints across the pavement ought to be 
J" wide. Rounding off the upper edges of all 
joints is an excellent protection against chip¬ 
ping and spalling. Contraction joints, made 
by inserting -J" steel plates at points equi¬ 
distant from the expansion joints, should be 
made, dividing the complete pavements into 
blocks or slabs about 10' or 12' square. 

All joints should be filled with an asphaltic 
filler of an approved type. 

Pavements, when completed, should be 
kept dampened for seven days at least, and 
kept free from traffic during that time. 

Concrete in Highway Construction. 

As distinguished from city pavements, 
suburban and rural roadways present many 
interesting problems to the road-maker. 
Many of these problems are conveniently 
solved when concrete is used. A number of 
advances have recently been made in the use 
of concrete for highways, with gratifying 
success. 

For example, several roads leading out of 
Detroit, Michigan, are constructed with a 
concrete pavement in the center, from 10' to 
18' wide. On either side of this roadway are 
laid shoulders of gravel or macadam, wide 
enough to take up the balance of the road- 
31 


CONCRETE PAVEMENT 

way, whatever its width may be, say 24' to 
30'. One highway of this general type was 
laid in 1909 and proved so satisfactory that 
in 1910 about fifteen miles of similar con¬ 
struction were put down. Cost has naturally 
varied, according to local conditions, but has 
averaged in the neighborhood of $1.35 per 
square yard of concrete. 

At Ann Arbor, Michigan, an interesting 
method for preventing spalling and chipping 
at the edges of expansion joints has been de¬ 
vised. It consists, briefly, in coating the sur¬ 
face of the finished roadway, which is laid 
under the general specifications for concrete 
roadways, with a surface painting of tar, cov¬ 
ered with a thin layer of fine gravel or coarse 
sand. The tar is applied after the concrete 
has set and when it is quite dry, and either 
hot coal-tar or distilled coal-tar is used. Ex¬ 
pansion joints are filled with a mixture of 
pitch or of tar and sand, and care is taken 
that the joints are filled perfectly flush with 
the surface of the pavement. Before the sur¬ 
face coating of tar has hardened a uniform,, 
thin layer of fine gravel, or coarse sand, is 
spread. 

In applying the tar, a steel tank, holding 
about 450 gallons, is used, with a fire-box be¬ 
low for heating the tar and keeping it liquid. 
It is fed to the surface of the street through a 
2" gas-pipe. As soon as the tar-wagon has 
passed, a rotary sweeper follows, distribut¬ 
ing the tar uniformly over the surface of the 
32 


CONCRETE PAVEMENT 


roadway. The sand is screened and then 
spread by a wagon carrying a triangular box. 
.Near the bottom of the box is a shaft geared 
to the hubs of the wagon wheels. As this 
shaft revolves, the sand is fed to a screen and 
from the latter distributed in an even layer 
over the surface of the roadway. 

The finished pavements resemble sheet 
asphalt. Glare and the reflection of heat are 
both overcome by the use of this method of 
surfacing. All cracks, joints and depressions 
are filled with the sand-tar mixture and dis¬ 
appear from sight. With the cushion on top, 
the expansion joints do not chip at the edges. 
Traffic is not noisy on pavement treated in 
this way and the waterproof coating assists 
the pavement in rapidly shedding rain water. 
In the possible event of cracks appearing in 
the body of the pavement, they are simply 
swept with the tar and sand mixture, when 
they are filled, and crumbling is prevented. 
In. brief, it may be said that the treatment 
overcomes, the objections that have been 
urged against concrete as a highway ma¬ 
terial. 

Cost of this treatment is reported to be 
about 2 cents per square yard, and since one 
treatment lasts for two years, it is extremely 
cheap. 




MAKING GOOD CONCRETE 


HOW TO MAKE GOOD CONCRETE. 

All concrete work, in order to be worthy 
of the name, must conform to certain definite 
methods of selecting and combining mate¬ 
rial. It is safe to say that errors of ignorance, 
carelessness or design, in selecting proper 
materials and in combining them have been 
responsible for every cubic inch of poor con¬ 
crete that has ever been produced. Using in¬ 
telligent care throughout every step of select¬ 
ing materials, combining them, mixing them, 
depositing them and curing them is the only 
possible way in which to secure good con¬ 
crete. It is believed that the following sug¬ 
gestions will be of value. They embody the 
recommendations of a number of practical, 
successful workers in concrete, men who 
recognize the value of the material and who 
are desirous of seeing nothing but the best 
concrete made. 

There are four absolute requisites for the 
manufacture of good concrete for any pur¬ 
pose—Portland cement, sand, gravel (or 
crushed stone) and water. Unless all of the 
ingredients are selected with a knowledge of 
what they ought to be, failure is a possibility. 

For the successful manufacture of con¬ 
crete for sidewalks, or for any other purpose, 
34 


MAKING GOOD CONCRETE 

it is obvious that the selection of the cement 
is of first importance. Thanks to the work 
done by the American Society for Testing* 
Materials, the N. A. C. U., the government 
laboratory for testing materials and the 
engineering bodies, a wholly definite stand-* 
ard for Portland cement has been formu¬ 
lated. Practically every Portland cement 
marketed in any considerable quantity today 
is made to conform with the accepted stand¬ 
ards of the American Society for Testing 
Materials, and the concrete man is safe in 
using any one of them, providing that con¬ 
ditions of storage have been proper. Side¬ 
walks are naturally subjected to constant 
exposure to the sun, wind and rain, and the 
best material is none too good for them. 

Portland cement must be “sound.” That 
is, it must be composed of the right propor¬ 
tions of silica, lime and alumina and the mass 
must be properly burned. When curing con¬ 
crete begins to break out into bubbles or 
blisters and the mass later begins to disinte¬ 
grate, it is too late to do very much but tear 
out the work and lay new, with resulting 
expense and loss. Free lime in cement is a 
pretty certain cause of this particular form 
of trouble, but to the casual observer free 
lime does not make its presence known at 
once. The writer has seen samples of cement 
which, when they were breathed upon, gave 
off very strongly the characteristic odor of 
lime. It is, of course, unwise to make use of 


35 


MAKING GOOD CONCRETE 

this class of cement, but there are also ce¬ 
ments that under most rough and ready tests 
appear to be of fairly good quality. Free 
lime, in the process of manufacturing ce¬ 
ment, is often protected from the action of 
moisture by the clinker that is formed in the 
burning process and it is only when it is 
impossible to remedy the difficulty, that is, 
after the cement has been used in concrete, 
that the lime is affected by moisture and 
trouble begins. It will be found an excellent 
precaution to confine one’s dealings to rep¬ 
utable firms of cement manufacturers, those 
with reputations to sustain or to make, and 
that are turning out their product in suffi¬ 
cient quantity to insure its being well aged, 
and not going directly from the kilns to the 
customer. Under the American system of 
Portland cement manufacture, the cement is 
ordinarily well aerated before it is even bar¬ 
reled, but a period of storage, under proper 
conditions, never harmed any cement, and it 
improves most of it In fact, one of the 
United States government’s requirements is 
that the cement used in government con¬ 
struction shall pass tests which show that it 
is thoroughly aerated. 

Grinding is an important branch of cement 
manufacture and the best specifications are 
definite on this point. The American Society 
for Testing; Materials, for example, requires 
in its specifications that cement, on being 
sifted, shall leave a residue of not more than 


36 


MAKING GOOD CONCRETE 

8 per cent on the No. 100 sieve. The Society 
has determined upon this specification only 
after exhaustive tests and all of the specifica¬ 
tion provisions have been demonstrated to be 
well within the bounds set by experience and 
practicability. It is safe to say that any ce¬ 
ment which comes up to these specifications 
is satisfactory to use and any manufacturer 
or dealer is ordinarily willing to demonstrate 
that his goods are up to the mark. 

The time of setting is also an important 
matter. Cement that does not set too quickly 
should be chosen. A “flash” set should be 
enough to cause the user to regard the 
cement under inspection with grave doubt. 
Those brands which attain their final set in 
from four to nine hours are to be preferred 
to those that set more quickly. Too rapid 
setting is often a sign of argillaceous matter, 
or clayey material. 

Good cement, however, hardens promptly. 
In other words, its final set should be 
achieved within a comparatively short space 
of time. Once the final set is accomplished, 
the process of hardening begins and con¬ 
tinues over a long space of time. The best 
cement, in general, is one that is compara¬ 
tively slow-setting and quick-hardening. 

In undertaking concrete work of any kind, 
the character of the Portland cement to be 
used is of the very first importance. Get a 
product that is sound, seasoned, finely 
ground, slow-setting and quick-hardening. 

37 


MAKING GOOD CONCRETE 

Have the man who supplies you satisfy you 
on these points, first of all. Have a clear 
understanding with him that if the cement 
does not come up to that mark, it will be 
rejected from your work. If the cement ful¬ 
fills these requirements you will have taken 
a long step toward preventing trouble of 
various kinds. 

Selecting the Sand. 

Hardness is one of the first considerations 
in the selection of sand for concrete work. 
Dirty sand can be washed and poorly graded 
sand can be rectified by the addition or sub¬ 
traction of the proper percentages of parti¬ 
cles of the right size. But sand that is soft 
is worse than useless. Any elements like 
clay, loam or silt are extremely detrimental, 
for two reasons. First, they are soft and 
soluble and readily wash out of the concrete, 
leaving voids in their places. Second, if they 
are finely divided, they coat the particles of 
sand, preventing the cement from bonding 
with them, thereby defeating the most im¬ 
portant function of the cement. Sand, ideal 
as to hardness and size of grains, is p'oor if it 
is dirty. To demonstrate the truth of this 
statement it is only necessary to make one 
batch of concrete with dirty sand and an¬ 
other with the same sand after washing. The 
difference in quality is apparent to the eye 
and under test the clean concrete shows 
great superiority. 


38 



MAKING GOOD CONCRETE 

Where it is possible to obtain it, sand with 
sharp grains is to be preferred to material 
with rounded elements. A simple test for 
determining both the cleanness of sand and 
the character of its grains is to rub a sample 
sharply between the hands. The peculiar 
“gritty” feel of the sharp sand and the ab¬ 
sence of stain on the palms are two points in 
favor of using the sand. Another good plan 
is to throw a handful- of the sand into a pail 
of water and let it stand for an hour or more. 
Dirt will be exposed by this method. If the 
sand is stirred up from time to time while it 
is under observation any mud or silt present 
will at last form a thin, slimy film on the 
upper surface of the mass. Particles of vege¬ 
table matter will rise to the surface of the 
water and clay and loam elements present 
will stain the water. If the sand is dirty, or 
if it shows the least sign of general softening 
or disintegration, it should be absolutely 
rejected. 

Sand may be hard and clean and still en¬ 
tirely unfit for use in concrete work of any 
kind. Proper grading in the size of the par¬ 
ticles is an essential, not only for the sake of 
good concrete, but for the sake of legitimate 
economy as well. Under modern designa¬ 
tion, sand is considered as material with its 
grains having a maximum diameter of J". 
Gravel runs in size from J" to 1", and larger 
sizes of aggregate come under the general 
head of crushed stone. 


39 


MAKING GOOD CONCRETE 

In order to determine with exactness the 
availability of sand, it should be subjected 
to the following analysis: A well mixed 
sample, of known weight, dry, should be 
washed carefully, dried and weighed again. 
The loss of weight in washing determines 
the percentage of soluble material present. 
The sample should then be screened through 
a set of sieves, ranging from the No. 8—that 
is, with eight meshes to the linear inch, or 64 
to the square inch—to the No. 200—with 200 
meshes to the linear inch, or 40,000 to the 
square inch. The percentages passing each 
sieve are plotted in a curve, using a parallel¬ 
ogram in which the vertical line represents 
the meshes per linear inch (with maximum 
diameter of particles passing) and the hori¬ 
zontal line represents percentages which 
pass. Comparisons of this curve with the 
normal curve show the exact percentages of 
material of a given size that must be added 
to or subtracted from the sand in order to 
make it conform most closely with the ideal, 
voidless sand. In the accompanying illus¬ 
tration, for example, is shown the curve 
drawn from an analysis of sand submitted to 
CONCRETE from a Michigan pit. Note that 
the size of particles passing the sieves is 
shown at the top of the figure, percentages 
passing are shown at the left, and the num¬ 
ber of meshes per linear inch in the sieves is 
shown at the bottom. Thus, about 2 per cent 
passed the 200-mesh sieve : about 24 per cent 


40 


MAXIMUM D/AMETER OE PART/CL ED 



<o 






<o 

<o 

05 

\ 

<\J 


S'3A 3/S' ON/EE Vd 30 VIM30333 


MESHES PER L/NEAR INCH 






































MAKING GOOD CONCRETE 

the 100-mesh, sieve; about 4 per cent the 80- 
mesh sieve; about 9 per cent the 60-mesh 
sieve; about 14 per cent the 50-mesh sieve; 
about 23 per cent the 40-mesh sieve; about 
34 per cent the 30-mesh sieve; about 50 per 
cent the 20-mesh sieve; about 56 per cent the 
16-mesh sieve; about 70 per cent the 12-mesh 
sieve; about 81 per cent the 10-mesh sieve, 
and about 85 per cent the 8-mesh sieve. 

If the sand under examination were ideal, 
that is, without any voids whatever, the per¬ 
centages passing the sieves of given mesh 
would be represented by the height on the 
vertical lines to which the dotted line rises. 
In other words, there would be about 10 per 
cent through the 60-mesh sieve, 24 through 
the 30-mesh sieve, 44 through the 16-mesh 
sieve; and so on. It is therefore a simple 
matter, by comparing the percentages that 
would pass in the ideal sand (represented by 
the dotted line) with those actually passing 
in the sample under examination, to deter¬ 
mine what percentage of material of a given 
size ought to be added to or subtracted from 
the sample in order to eliminate voids. In 
the chart in question, there would have to be 
added about 1 per cent of the material that 
passes a 200-mesh sieve; 2 per cent of the 
material that passes a 100-mesh sieve; 4 per 
cent of the material that passes an 80-mesh 
sieve. The amounts passing the 60-mesh 
sieve coincide with almost perfect exactness. 

There would have to be subtracted about 


42 


MAKING GOOD CONCRETE 

2 per cent of the material passing the 50- 
mesh sieve; about 5 per cent of the material 
passing a 30-mesh sieve; about 18 per cent 
of the material passing a 20-mesh sieve; and 
so on. When the sample’s curve falls below 
the ideal curve, it is obvious that sufficient 
material of such a diameter as will pass the 
sieve of the same mesh must be added to the 
sample, in order to make the curves coincide. 
When the sample’s curve falls above the 
ideal curve, material must be subtracted. 

The computation in the present case may 
seem somewhat long and tedious, but in a 
full-size blue print the amounts are very 
readily determined. In the sample of sand 
under discussion, there are no striking differ¬ 
ences between the sample curve and the ideal 
curve; and practically no rectification of the 
aggregates, by addition or subtraction, is re¬ 
quired. In many samples, however, the sam¬ 
ple’s curve goes very much above or below 
the ideal, and since the chart shows definitely 
how far it goes either way, and at the same 
time shows a definite percentage, in terms of 
particles of a definite diameter, it is a simple 
matter to note the difference and make the 
proper addition or subtraction. Suppose, for 
instance, that in a sample of sand run 
through the sieves, the percentage of parti¬ 
cles passing the 16-mesh sieve was as high 
as 80. This would be rather an extraordi¬ 
nary case, but is suggested merely by way of 
illustration. The curve on the chart would 


43 


MAKING GOOD CONCRETE 

show a high point or peak, with its top at 
80 per cent. The percentage for the ideal 
curve is only about 42, or 38 less than that 
shown by the sample suggested. If 38 per 
cent of the particles of the samples passing 
the 16-mesh sieve were subtracted from the 
sample as a whole, the sample would obvi¬ 
ously be greatly improved. 

This matter has been gone into at consid¬ 
erable length in the belief that it is compara¬ 
tively little understood and because it is 
known to be one of the utmost importance. 

In the place of sand, where this material is 
not readily obtainable, it is profitable to use 
crusher screenings. The chief objection to 
their use lies in the possible presence of a 
comparatively high percentage of crusher 
dust or “flour.” Any considerable amount 
of this element certainly weakens the con¬ 
crete. A sieve analysis of the crusher screen¬ 
ings will at once determine their fitness for 
use. What has been said about cleanliness 
and hardness of sand applies with equal force 
to crusher screenings and, indeed, all other 
material for concrete. Crushings from the 
hardest stones, like granite or trap, are the 
best to use. 

Gravel. 

All that has been said of sand in general 
is perfectly applicable to gravel used in con¬ 
crete work. A sieve analysis, using stone 
screens with large mesh, is of great service 
44 


MAKING GOOD CONCRETE 

in a definite determination of its fitness for 
use. 

Cinders. 

In sidewalk concrete the use of cinders as 
a part of the mixture is not advisable where 
any other aggregate is available. Under 
proper specifications cinders add to the fire¬ 
proof qualities of floors and arches, but in 
sidewalks they are of no special value, and 
if not the right kind they are very likely to 
be the source of trouble. Where there is lime 
in the ash, or sulphur, as there is almost in¬ 
variably, the surface of the walk will become 
pitted. Where it is necessary to make use of 
cinders get them free from unburned coal, 
and use about 25 per cent extra of sand to 
fill the higher percentage of voids. 

Crushed Stone. 

What has been said of gravel applies with 
equal force to the selection of crushed stone. 
Since the strength of concrete depends on 
the hardness of the materials of which it is 
composed, it is obvious that the strongest 
material makes the strongest concrete. 

The general theory of making strong con¬ 
crete is based upon having the material of 
sizes so graded that the smaller particles fill 
the spaces between the larger ones. Under 
ideal conditions there would be no spaces at 
all. The particles of sand would fill the 
spaces between the particles of gravel or 
45 


MAKING GOOD CONCRETE 

crushed stone and the cement in turn would 
fill the spaces between the particles of sand. 
The best concrete results when every sepa¬ 
rate grain of sand is covered with cement, so 
as to make a mortar, which in turn covers 
each particle of the aggregate and binds the 
whole mass strongly together. 

Water. 

Water for use in the manufacture of good 
concrete must be clean and pure, in that it 
is free from alkali, sulphur, iron or discolora¬ 
tion. The water serves a most important 
purpose in setting up the chemical action of 
crystallization in the cement, without which 
it does not harden. The presence of impuri¬ 
ties of. any kind in the water results in dis¬ 
coloration of the sidewalk, while dirt, dust 
and so on may have the effect of forming a 
thin film between the lower and the upper 
coat, with the result that they will not bond 
together. A soft water, clean and clear, used 
not too cold, will give the best results. 

Mixing. 

Cement sidewalks are ordinarily made in 
two sections, a bottom and an upper coat. 
Where gravel is to be used in the lower coat, 
the proportion should be 1 part of Portland 
cement to 4 parts of clean, hard gravel, with 
graded sand enough to fill the voids in the 
gravel. An average rule for the amount of 


46 


MAKING GOOD CONCRETE 

sand would be to use one-fourth as much of 
this material as gravel, so that the bottom 
coat is made up of 1 part of cement to 5 of 
aggregate. 

If crushed or broken stone is used instead 
of gravel, it is best to use 1 part of Portland 
cement, 2 parts of clean, sharp sand and 4 
parts of broken stone. The larger quantity 
of sand is used because of the larger number 
of voids to fill. 


Manipulation. 

Machine mixing is by far the most satis¬ 
factory from all standpoints, and mechanical 
mixers ought to be used wherever possible. 
If for any good reason their use is imprac¬ 
ticable, the following method gives good 
results: 

The gravel or stone should be spread out 
in a layer on the mixing platform or in a 
shallow box, covering it with the sand, also 
in a layer, and afterward with the cement. 
If this dry mass is cut through from the top 
to the bottom, a uniform mix will be assured. 
The mixing should be thorough and the 
mass should be well turned over at least 
twice before any water is added. 

Water is put in in small quantities, from 
a hose with a spray or sprinkler attachment, 
and the mass is manipulated until it is of the 
desired consistency. This is such that the 
mass looks and acts like a stiff jelly, but it 


47 


MAKING GOOD CONCRETE 

should stand up well after it is tamped into 
place. 

Another method that has many advocates 
is to spread the sand out first, covering it 
with the cement, and mix the two until the 
consistency of the mass is uniform, that is, 
until the cement is thoroughly distributed 
through the sand. Then add water in the 
form of a spray until the mass is plastic. It 
may now be spread out on the platform or 
bottom of the box and the coarser aggregate, 
previously well moistened, added. The mass 
is then thoroughly turned at least twice, 
when it is ready to place in the prepared site 
of the walk. 

Water may be added by the pailful or in 
any other way by means of which it may be 
conveniently measured; but it is important 
that it shall not be dashed violently into the 
mixture. 

As a general proposition/it is best not to 
make up more than a cubic yard of concrete 
at any one time, in order to secure thorough 
mixing of the batch. The fresh concrete may 
be transported to the sidewalk site in wheel¬ 
barrows, and a good test of the proper con¬ 
sistency of concrete is that it does not 
“quake” after it is loaded into the barrow. 

Preparation of the Site. 

The location of the walk once being deter¬ 
mined, the site should be carefully staked 
off, running the lines such a distance apart 
48 


SIDEWALK SUGGESTIONS 

that the distance between them is 4" wider 
than it is desired to make the finished walk. 
All roots of trees and other wood or material 
liable to decomposition should be carefully 
removed. So should all large stones, pieces 
of sod or turf, and other obstructions to a 
clear excavation. Where soft spots are un¬ 
covered in the process of excavation, they 
should be filled in with solid material, prop¬ 
erly tamped to a good bearing surface. 

The heaving and throwing of walks, so 
often attributed to tree roots growing up 
under the walks, if more often the result of 
the movement of the earth caused by the 
swaying of nearby trees. Roots, however, do 
grow close to the stone, as they find moisture 
there, and elm and maple roots should be 
looked after especially, as they are likely to 
cause the most trouble. 

Sub-Base. 

No deep excavation for sidewalk founda¬ 
tions is necessary, except in very extraordi¬ 
nary cases. The practice of excavating a 
trench a foot deep and then filling in 8" or 
so has been almost universally dispensed 
with, and with excellent results. It will gen¬ 
erally be found satisfactory to remove the 
sod and top soil to a depth equal to that of 
the finished walk, as planned. In what little 
foundation work is done it will be found ad¬ 
visable to tamp in thin layers, thus giving a 
more solid base for the concrete. 


49 


SIDEWALK SUGGESTIONS 

In the excavation should be placed a foun¬ 
dation of sand and broken stone, or gravel, 
with the sizes well graded, so that when 
tamped it presents a hard and uniform sur¬ 
face. Where ashes or cinders are used in this 
foundation and it is laid so as to be porous, 
agricultural tile should be laid to drain off 
any water which might otherwise accumu¬ 
late and freeze, with resultant damage to the 
walk. 

The foundation should be thoroughly 
moistened, to the same extent as the fresh 
concrete, before the latter is laid upon it. 
This should be dumped in and tamped down 
to a thickness ranging from 4" to 6", accord¬ 
ing to location and specifications required. 
As soon as the bottom coat is tamped, and 
before it has had time to set, the top coat 
must be added. 

Tools. 

Devices of various shapes are on the mar¬ 
ket for the use of sidewalk workers. These 
consist of rollers, jointers, groovers, edgers, 
tampers, trowels, floats, and so on. They are 
practically essential to securing a neat finish 
and appearance. Care should be exercised in 
the selection of tools, for there are some on 
the market which will not stand the strain 
of continued use. 

Curing and Protection. 

As soon as the walk is completed, it should 
be carefully moistened and kept under cover 
50 


SIDEWALK SUGGESTIONS 

from wind and sun for at least three days. In 
hot weather the walks should be moistened 
in the morning and the evening, when the 
sun is not too hot. This practice prevents 
the cement from drying out too fast, with 
resultant weakening and bleaching. General 
practice recommends the erection of a canvas 
screen over and around the work, the mate¬ 
rial being set on a slant, so as to drain rain 
water off. 

If the walk is laid in freezing weather, 
warmed materials are essential. The water 
must be at least lukewarm and the sand and 
gravel or stone free from frost. For protect¬ 
ing the work from injury by cold, different 
contractors use different means. Paper, saw¬ 
dust, sand, shavings and even manure are 
used to cover the work and protect it. Tar 
paper is also utilized. It is recommended 
that the covering be permitted to remain on 
work laid in freezing weather for at least 
three weeks. 

Cost of Walks. 

Most books dealing with sidewalk con¬ 
struction say practically nothing of the 
important subject of costs. This omission 
is the result of the fact that it is impossible 
to give cost figures for one locality that are 
of much benefit in another. In the larger 
cities, for example, where material has to be 
hauled a considerable distance, as in the case 
of sand and gravel, and where the labor costs 

51 


SIDEWALK SUGGESTIONS 

are high, the cost of a concrete sidewalk is 
necessarily comparatively large. Prices of 
all kinds of material, from cement to water, 
vary very widely in different sections of the 
country and in different communities. 

A fairly large canvass of representative 
contractors and sidewalk men has failed to 
establish any good average cost. The sec¬ 
tion of this book which deals with the 
amounts of material required for sidewalks 
of various thicknesses will be found helpful 
in estimating the quantities of each required 
and the local cost being known the contrac¬ 
tor can figure with fair accuracy on what his 
work will cost him, finished. 

Estimating on Work. 

One barrel of Portland cement, it is esti¬ 
mated will lay about 60 square feet of walk, 
5" thick at the middle and 4" thick at the 
edges, 6 ' wide, when mixed in the propor¬ 
tions suggested in foregoing paragraphs. 
Knowing the cost of sand, gravel and labor, 
the sidewalk maker can form a fairly good 
idea of what the walk is going to cost him 
to lay and what he ought to charge for it in 
order to make a fair profit. Good walks are 
the best advertisement, and a neat nameplate 
set into the surface of the finished walk is an 
excellent business card. The man who makes 
a reputation for walks that look well and 
wear well will have no difficulty in obtaining 
a fair price for his work. 


52 


SIDEWALK SUGGESTIONS 

Street Crossings. 

The foundation for concrete street cross¬ 
ings should be the same as for sidewalks. 
The base should consist of a layer 4J" deep, 
composed of 1 part of Portland cement and 
4 parts of clean sand and gravel, thoroughly 
mixed dry, properly wetted, and tamped to 
uniform grade. The surface should consist 
of a layer 1 thick, composed of 1 part Port¬ 
land cement and 1J parts of good, clean, 
sharp screened sand, thoroughly mixed 
when dry and wetted to the consistency of 
thick mortar. This top surface should be 
thoroughly troweled into the base and fin¬ 
ished to conform with the grade established 
by the city engineer. 

Curbing. 

After excavating to a proper depth, set 
frames for curbing with spreader board be¬ 
tween, not less than 4' apart. Brace frames 
thoroughly opposite these spreading boards, 
keeping the outside frame at all times in line. 
Concrete for curbing should be composed of 
1 part Portland cement to 5 parts clean, 
sharp sand and gravel, thoroughly mixed dry 
and then wet to a proper consistency. After 
the concrete has been thoroughly mixed, 
tamp in place, using sheet iron division plates 
to cut the curbing in sections not less than 4 ' 
nor more than & in length. The top coat of 
curbing should be at least in thickness 
53 , 


SIDEWALK SUGGESTIONS 

and should consist of 1 part of Portland ce¬ 
ment to 2 parts of clean, sharp, screened 
sand, and should be thoroughly smoothed off 
with a trowel on the edges and finished to its 
desired shape with an edger or curb tool. 

For business streets, curbing should be 
from 18" to 22" deep and 5" in thickness at 
the top and 7" at the bottom. For residences 
curbing may be 14" or 16" in depth, but of no 
less thickness than for street curbing. 

There has been a great deal of discussion 
as to whether it is best to put the curbing on 
a business street outside of the walk or let 
the walk rest on the curbing. Experience 
has shown the latter method to be prefera¬ 
ble; that is, let the walk rest on the curbing. 
This allows the walk to slide back and forth 
on the curb as it expands and contracts with¬ 
out disturbing the curb, while if the curb is 
placed outside the walk the expansion of the 
walk may displace it. 

Reinforced Sidewalks. 

If necessity requires that a sidewalk shall 
be built in such a location that the support¬ 
ing soil is likely to be washed from beneath 
it, reinforcement is an excellent precaution. 
We have in mind such walks as are some¬ 
times built on sandy soil, in locations liable 
to attack from unusually high water. If the 
sidewalk builder will lay a mesh of expanded 
metal, the width of the walk, and about 2" 
from the lower level of the bottom coat, he 
54 


SIDEWALK SUGGESTIONS 

will have a construction that will at least 
support its own weight until such time as the 
underpinning can be replaced and tamped to 
a solid bearing surface. A 6" mesh should 
be ample for all ordinary purposes. 

Hints and Suggestions. 

Do not attempt to use a mixture of con¬ 
crete after the set has begun. 

Avoid the use of sand that is too fine. If 
you use it, you will have trouble. 

Moisten the coarse aggregate well before 
adding the cement. It assists the cement in 
adhering to the particles. 

Don't scatter Portland cement on the sur¬ 
face of your finished work. If you do, you 
will have difficulty at that particular point. 

In preparing the excavation for a cement 
sidewalk, absolute drainage is essential, if 
trouble from freezing water, with conse¬ 
quent expansion, is to be avoided. 

Shade trees should be set not less than 4' 
from the walk and in the case of trees whose 
roots run close to the surface of the ground, 
a distance of Kfi is still better. 

Union between the top and the bottom 
coat is best accomplished by tamping them 
together. Have enough water so that the air 
in the concrete will escape when the tamping 
is done. 

Be sure that your bottom coat is still moist 
and fresh when the top coat is applied. 
Otherwise, the two will not join. Be careful, 
55 


SIDEWALK SUGGESTIONS 

too, that no dust or dirt is lying on the bot¬ 
tom coat, or you will fail to get a bond. 

A barrel of cement will give, in the propor¬ 
tions of 1 part of cement, 2 \ sand and 5 gra¬ 
vel for the bottom course, and 3 of sand to 5 
of cement for the top course, 25 square feet 
of walk 8" thick and 55 square feet of walk 
5" thick. 

Some walk-makers sprinkle thoroughly 
slacked lime that has been finely ground, on 
the surface of the walk before it has begun 
to harden. This practice tends to delay the 
set a little and also produces a good color 
effect. Lime that has been prepared in this 
manner, added to the cement used in the top 
dressing or coat, will whiten the walk and 
assist in shedding the water. 

Finish the walk while the upper surface is 
still moist and easily worked. Avoid too 
much use of the trowel. In the action of this 
tool, a vacuum is created between the sur¬ 
face of the walk and that of the trowel, with 
the result that particles of neat cement are 
drawn to the surface, where they dry out and 
are worn off, with the result that the top 
coat is robbed of its proper proportion of 
cement. If the walk is finished after it has 
begun to set. the resulting surface will be 
brittle and will crumble easily. 

Where broken brick and cinders are used 
in filling in the excavation, it is wise to tamp 
them as solidly as possible and to cover them 
with a layer of sand in order to prevent op- 
56 


SIDEWALK SUGGESTIONS 

posite action in expansion from freezing. 
One contractor explains the action of frost 
in cracking walks by saying that the ground 
expands, owing to the action of the freezing 
water, while the hardened cement contracts 
from the cold. The two forces act in direct 
opposition, so some means should be taken 
to prevent the sub-soil from freezing to the 
lower surface of the walk. Careful provision 
for thorough drainage will avoid this danger. 

Albert Moyer, a sidewalk expert, suggests 
the advisability of making the entire walk a 
uniform slab of closely compressed, carefully 
selected stone. Just before the surface dries, 
he advocates scrubbing it with a wire brush, 
of the kind used in cleaning boilers. A gentle 
stream of water played from a hose in the 
path of the brush will assist in removing the 
thin skin of neat cement which gives the 
walk its original neat finish, but which in 
time wears off under traffic. For walks in 
which appearance is not the first considera¬ 
tion, this suggestion is an excellent one, as 
it produces a walk of first-rate wearing 
qualities. 

Cellar Floors. 

In laying cellar floors the methods differ 
somewhat from those, employed in sidewalk 
construction. Owing to the fact that the con¬ 
crete is not exposed to the action of wind 
and weather, there is a great deal less expan¬ 
sion and contraction, and in floor work under 


57 


MISCELLANEOUS 


shelter, expansion joints are dispensed with, 
except in very large floors. They are not re¬ 
quired in ordinary residence construction. 

For ordinary cellar floors, a layer of con¬ 
crete not less than l\" thick, over a 4" bed 
of cinders, is generally sufficient. The con¬ 
crete should be mixed in the proportion of 
1:3, with bank-run sand and gravel, and 
floated to a level. 

Drainage is an important point to consider 
in cellar work, and where floors are to be laid 
on clay, sub-drainage, with tile or otherwise, 
should be provided. 

Repairing Plank Walks. 

It often becomes necessary under a city 
ordinance to build a new wooden walk when 
the old plank are perfectly good, on account 
of the stringers being too rotten to hold a 
nail. This expense can be avoided by put¬ 
ting in a concrete stringer without disturb¬ 
ing the plank. To do this, dig a small trench 
under each side of the walk, extending about 
4" under and about 4" deep; drive spikes into 
the plank about 2" from the edge of the walk, 
so as to extend down into the trench. Then 
All the trench with concrete, tamping it up 
to the plank. If the plank are warped up at 
the end, weight them down until the nails are 
firmly set in the concrete stringer. This will 
insure you a foundation that will outwear 
your plank. Should there be any holes in 
the walk, cut out the rotten wood, fill in the 


58 


MISCELLANEOUS 


cavity (if more than 3" deep) with cinders 
well tamped; then fill with concrete to the 
surface. At a very small cost, an old walk 
may in this way be kept in repair for years. 

Concrete Floor Over Wood Floor. 

Many times it is desired to replace an old 
wood floor with one of concrete. This can 
be done by laying the new floor over the old. 
In preparing for this, examine all the joists 
well, nail down all loose boards, and during 
the construction and curing of the work, 
shore up all weak spots that may manifest 
themselves. Lay on the floor expanded 
metal or heavy wire cloth of not over six- 
inch mesh, tying down the ends with light 
wire staples. The strips should overlap one 
another about three inches. Wet the floor 
thoroughly. 

Upon this, lay a course of concrete about 
1\” thick, except on driveways, where it 
should be thick. Lay the floor in 4' strips, 
returning after each operation and finishing 
that strip with a wooden float after leveling 
with a straight-edge. Repeat this operation 
the entire length of the floor. Be careful not 
to fracture the floor after the process of crys¬ 
tallization has started. This accident is likely 
to be caused by the springing action of some 
of the boards adjacent to the newly-laid con¬ 
crete. 

The mixture should be 1 part Portland ce¬ 
ment to 3 parts bank-run sand and gravel, 
59 


MISCELLANEOUS 


to be laid in one continuous layer. Gutters 
may be formed where necessary. This pro¬ 
cess will be found valuable in repairing old 
barn floors and has been used with great 
success in any number of instances. 

Forms and Dividing Plates. 

Recognition of the necessity of providing 
some certain means to secure definite joints 
as a protection against possible damage due 
to expansion and contraction, early led to the 
invention and marketing of dividing plates. 
These originally took the form of slotted 
metal strips, about J" thick, the slots being so 
arranged as to engage the edges of the 2x4’s 
formerly used at the sides of the walks. Their 
use became so popular that other and more 
nearly complete metal form systems were 
placed on the market. Today there are sev¬ 
eral ingenious devices in metal which require 
to be held with long steel pins only, in order 
to provide a rigid, accurate and durable 
means for confining the concrete entering 
into the construction of the sidewalk. Flex¬ 
ible strips provide for curves of any desired 
radius and means for making the form and 
dividing plates a single unit have been in¬ 
vented. The old wooden strips are properly 
becoming less common. With anything like 
reasonable care, the metal forms last a long 
time, and their use results not only in better 
work but actually in lowered expense for 
construction. 


60 


MISCELLANEOUS 


In use, the forms and strips are oiled or in 
some other manner prepared so that the 
green cement will not adhere to them when 
it has set. As soon as the concrete has begun 
to harden, the forms and plates are raised 
and the completed walk is left, with clean, 
smooth edges and definite expansion joints, 
going through both the top and the bottom 
coat of the walk, down to the foundation. 

What has been said in regard to sidewalk 
construction applies with equal force to the 
construction of other pavements for similar 
purposes — station platforms, hall-ways, 
floors in buildings and basements and so on. 
The American farmer, ever alert to take up 
the new thing of value, has laid thousands of 
square feet of feeding floors for his stock, 
within a comparatively short time. 

Where sidewalks are of necessity pierced 
by iron pipes, manholes, posts or other metal 
members, expansion joints, with a thickness 
of at least -J", should be provided. 

In providing drainage underneath side¬ 
walks, a fall of at least J" to every running 
foot should be provided. It cannot be empha¬ 
sized too strongly that the accumulation of 
water underneath a sidewalk opens the way 
for damage. When the water freezes, the ice 
expands. Concrete, on the other hand, con¬ 
tracts in the cold, and the resultant opposed 
forces are bound to result in serious trouble. 

Be careful to see that your foundation of 
cinders, broken brick or what not, when, for 


61 


MISCELLANEOUS 


any good reason, one is provided, is thor¬ 
oughly soaked with water before the con¬ 
crete for the lower coat is placed. If this 
precaution is not taken, it is certain that the 
porous material, absorbing a considerable 
quantity of water, will rob the lower coat 
concrete of much of the moisture it needs 
for proper crystallization and curing. 

For floors to be used in slaughter-houses, 
where a non-absorbent quality is, of course, 
a necessity, Albert Moyer, a well known au¬ 
thority, suggests the use of concrete mixed 
with oil. Owing to the alkaline qualities of 
the cement, when it is mixed with water and 
with oil an emulsion is formed, with tfre re¬ 
sult that the cement, oil and water are thor¬ 
oughly incorporated in the concrete. From 
10 per cent to 15 per cent of non-volatile min¬ 
eral oil is used, the oil being thin enough to 
pour readily. Mineral oil of this character 
weighs from 7 \ to 8 pounds per gallon. 

In practice, the oil in the percentage 
named is added just after the water and the 
mixing proceeds as usual. The same amount 
of careful mixing is necessary when oil is 
used as when it is omitted. The use of oil 
slightly delays the final set of concrete, but 
not to a very great extent. 

Color for Sidewalks. 

The following table of colors is suggested 
for a 1:2 mortar, used as the top dressing of 
a sidewalk. The quantities shown are those 


62 


MISCELLANEOUS 


required for each 95 pounds (1 bag) of Port¬ 
land cement utilized. 

Color. Material. Quantity. 

Black..Excelsior Carbon Black... 2 lbs. 

Black...Manganese Dioxide .10 lbs. 

Buff.Yellow Ochre . 4 lbs. 

Blue.Ultramarine or Azure Blue. 4 lbs. 

Gray.Lamp Black (Bone Black). y 2 lb. 

Green.Ultramarine . 7 lbs. 

Green.Oxide of Chromium... 7 lbs. 

Brown.Roasted Iron Oxide. 6 lbs. 

Red.Raw Iron Oxide . 6 lbs. to 10 lbs. 

Bright Red ... .Pompeian Red . 6 lbs. 

Yellow.Ochre . 6 lbs. 

These colors should be mixed thoroughly 
with the sand or screenings used. 

To be at all satisfactory, colors must obvi¬ 
ously be permanent in character. Mineral 
colors are the only ones that answer this re¬ 
quirement, and care should be taken in their 
purchase. There are several reputable deal¬ 
ers in material especially designed for use in 
concrete work. 

0 

Shop-Made Sidewalks. 

In the manufacture of concrete, as in any¬ 
thing else, a constant product results only 
from constant conditions. Two batches of 
concrete made under exactly the same condi¬ 
tions must obviously be identical in charac¬ 
ter. The nearest approach to constant con¬ 
ditions obtains in a factory, where the pro¬ 
duct is made of selected, inspected material, 
using the same quantities of each, under 
careful inspection. Where methods of manu- 
63 




















MISCELLANEOUS 


facture, including the important item of cur¬ 
ing, are constant, good concrete results. 
These facts have suggested the advantages 
of concrete sidewalks laid as flagstone walks 
used to be laid. The preparation ohthe foun¬ 
dation bed and the provision of a cushion of 
sand are, of course, the same for concrete 
slabs as they were for the old stone walks. 
Slabs of the desired dimensions, plain or re¬ 
inforced, are readily made in a concrete pro¬ 
ducts plant and kept in stock for use as re¬ 
quired. Within certain reasonably close lim¬ 
its, slabs for reinforced sidewalks and for 
floors are alike. Their manufacture offers 
attractive possibilities to the man who has a 
proper plant for the manufacture of concrete 
products. 

For the best results, concrete should not 
be thrown with a shovel a distance of more 
than 4', nor should it be dropped through a 
greater distance. In traversing greater dis¬ 
tances, the particles of aggregate become 
separated, and instead of remaining a homo¬ 
geneous mixture, all the larger particles of 
gravel or stone are found at the bottom. 

A popular method of figuring labor costs 
is to estimate that six men will finish about 
700 square feet of concrete walk in a day, 
where the work has a thickness of 4". The 
gang in this case would consist of five labor¬ 
ers and one finisher. This is simply an em¬ 
pirical method of estimating. The only safe 
way to arrive at costs is to keep your own 
64 


MISCELLANEOUS 


cost data on each job, with full notation of 
conditions. In a comparatively short time, 
you will have valuable material for estimat¬ 
ing other work of the same character. 

Experts of the Atlas Portland Cement Co. 
suggest the following tables of quantities re¬ 
quired, which will be found very useful in 
computing costs for sidewalk construction: 


MATERIALS FOR 100 SO. FEET OF CONCRETE. 


Bags of Cement to 100 Sq. Feet of 
Concrete Surface. 
Thickness Proportions 


Inches 

l:iy 2 :3 

1:2:4 

1 :3 :6 

3 

8 4 

6)4 

4 H 

4 

11 

84 

6 

5 

14 4 

11 

7)4 

6 

1634 

13J4 

9)4 

8 

2234 

18 

12 

10 

284 

21)4 

15)4 

12 

3434 

25)4 

18)4 


Bags of Cement to 100 Sq. Feet of 
Mortar Surface. 


Thickness 

Inches 

1 :1 

Proportions 

1 :154 

1 :2 

4 

3)4 

234 

24 

34 

5 

4 

34 

1 

7 

54 

44 

1 4 

84 

6)4 

5 34 

1)4 

10 

8 

64 

134 

12 

94 

74 

2 

14 

11 

9 


SURFACES LAID WITH ONE BARREL OF CEMENT. 


No. of Sq. Ft. of Concrete (Base) No. of Sq. Ft. of Mortar Surface 
Laid with 4 Bags (1 Bbl.) Laid with 4 Bags (1 Bbl.) 

of Cement. of Cement. 


Thickness 
Inches 1 

:14 

Proportions 
:3 1:2:4 1 

:3 :6 

Thickness 

Inches 

1 :1 

Proportions 

1 :1 4 

1 :2 

3 

47 

60 

83 

4 

114 

146 

178 

4 

36 

46 

66 

4 

80 

100 

114 

5 

27 

36 

52 

l 

57 

73 

89 

6 

24 

30 

41 

14 

48 

60 

70 

8 

17 

22 

33 

14 

40 

50 

59 

10 

14 

19 

26 

14 

33 

43 

52 

12 

12 

15 

21 

2 

29 

36 

44 


Note.—Four bags of cement equal 1 barrel. 

For proportions 1:1J4:3 use for every 33 bags of cement 1 large 
double load of sand and 2 of gravel. 

For proportions 1 :2:4 use for every 23 bags of cement 1 large 
double load of sand and 2 of gravel. 

For proportions 1:3:6 use for every 15 bags of cement 1 large 
double load of sand and 2 of gravel. 

One large double load contains 40 cubic feet, or 14 cubic yards. 


No material used in the top' dressing 
should be utilized if more than 30 minutes 
have elapsed from the time of its being 


65 


MISCELLANEOUS 


mixed. If the concrete has not hardened, 
however, it may be used in the base. 

For the man who wants to build sidewalks 
as a business, that is, the concrete sidewalk 
contractor, the patented forms of metal, now 
on the market are practically essential. For 
the farmer, however, or for the man who 
wants to lay a small sidewalk for himself, the 
following suggestions, taken from the side¬ 
walk specifications of the Universal Portland 
Cement Co., Chicago, Ill., are of value: 

Equipment for mixing concrete should be 
a tight platform about 7'x 12', square- 
pointed shovels, a mortar hoe, steel-body 
wheelbarrow, sand screen, mortar box, water 
barrels, buckets and a measuring box, hold¬ 
ing 4 cubic feet. 

A well-made platform for mixing concrete 
should be part of the regular equipment of a 
farm, and it will be cheaper to build a good 
one at the outset than to waste time and 
money in constructing and using temporary 
ones. Such a platform as is suggested can be 
built of 2" lumber nailed upon three 2" x 4" 
stringers, rounded on the ends. The outside 
stringers should project a little beyond the 
edges of the platform and be bored for clevis 
irons, so that the platform may be dragged 
about the farm by a team. The rounded ends 
of all the stringers will facilitate transporta¬ 
tion. 

To make the platform there are required: 

66 


MISCELLANEOUS 


12 pieces 2" x 12" x 7', dressed on one side 
and two edges. 

2 pieces 2" x 2" x 12', dressed on one side 
and two edges. 

2 pieces 4" x 4" x 13', rough. 

1 piece 4" x 4" x 12', rough. 

Dressed lumber will provide a smooth and 
tight platform, with resultant decrease of 
labor in shoveling. Care must of course be 
taken to have the lumber free from warp, in 
order to make tight joints between the 
planks. 

Methods of mixing concrete on a platform 
have already been suggested under “Hand 
Mixing.” (Which see.) 


67 


INDEX 


Aggregates, Curb and Gutter. 13 

Sidewalk Work . 4 

Amount in Walk from 1 Bbl. Cement. 55 

Area of Slabs in Sidewalks... 7 

Bag of Cement, Cubic Contents. 8 

Bag of Cement, Weight of. 7 

Base, Roadways and Streets. 22 

Sidewalks . 7 

Batch, Best Size of. 48 

Brick Walks, Disadvantages of. 3 

Cellar Floors . 57 

Choosing Portland Cement . 36 

Cinders, Disadvantages of. 45 

Cities Using Concrete Pavement. 27 

Coarse Aggregate, Maximum Size. 5 

Cold, Protecting Sidewalks from. 51 

Color for Sidewalks . 62 

Coloring Matter, Curb and Gutter. 18 

Method of Mixing. 10 

Concrete, Curb and Gutter. 15 

Concrete Floor over Wood Floor. 58 

Concrete Pavements . 26 

Construction, Curb and Gutter. 15 

Corrugations in Paving. 30 

Cost of Sidewalk Work . 51 

Cost of Surfacing, Highways. 33 

Costs, Labor, Method of Figuring. 64 

Costs, Paving . 28 

Crushed Stone, Requirements for. 45 

Crusher Dust, Danger of. 44 

Curb . 53 

Business Streets . 53 

Dimensions of . 15 

Location of ... 54 

Residence Streets . 53 

Curb and Gutter Work. 12 

Aggregates . 13 

Size of . 13 

Concrete for . 15 

Construction . 15 

Expansion Joint Filler . 13 

Forms . 14 

Materials ...,. 12 













































INDEX 


Mortars . 

Natural Deposits of Sand. 

Protection . 

Sub-Base . 

Sub-Grade .. 

Water . 

Wearing Surface . 

Curing, 

Curb and Gutter . 

Pavements . 

Sidewalks . 

Dirt on Base, Danger of. 

Dividing Plates . 

Drainage, Essential . 

Grade Required for . 

in Cellar Floor Work. 

Durability of Concrete Walks. 

Edges, Curb, Radius for. 

Edges of Slabs, Rounding. 

Estimates, Materials for. 

Estimating Sidewalk Work . 

Expansion Joints . 

Curb and Gutter . 

Distance Apart . 

Pavement . 

Roadways and Streets . 

Where Metal Pierces Concrete. 
Expansion Joint Filler, Curb and Gutter 

Farm, Sidewalks for the. 

Farm Sidewalks, Equipment for. 

Fine Sand, Avoidance of. 

Floor, Concrete, over Wood. 

Floor, Wood, Concrete over. 

Floors, Cellar .. 

“Flour,” Danger of. 

Forms and Dividing Plates. 

Forms, Curb and Gutter. 

Roadways and Streets . 

Sidewalk . 

Sidewalks, Must be Moistened.... 

Strength of .. 

Freezing Weather, Sidewalk Work in.. 

Work in . 

Good Concrete, How to Make. 

Grade of Walks . 

Gravel, Analysis of . 

Requirements for . 


13 

13 
18 

14 

14 
13 

17 

18 
31 

50 

9 

59 

55 

61 

57 
3 

18 

10 

64 
52 
22 

15 
7 

31 

22 

61 

13 

65 
65 
54 

58 

58 
57 
44 

59 

14 
22 

6 

22 

6 

51 
9 

34 

6 

44 

44 
















































INDEX 


Gutter (See Curb) . 12 

Hand Mixing . 47 

Hard Aggregate, Advantage of. 44 

Heaving of Walks . 49 

Highway Construction .,. 31 

Highways, Ann Arbor, Mich. 32 

Detroit, Mich. 31 

Hydrated Lime, Sidewalk Surface . 56 

Ideal Concrete . 45 

Joints, Treatment of, Paving. 31 

Keeping Work Moist . 55 

Labor Costs, Method of Figuring. 64 

Loam, Danger of. 4 

Manipulation of Concrete . 47 

Materials, Curb and Gutter. 12 

Roadways and Streets . 19 

Sidewalk Work . 4 

Machine Mixing, Preferable .8, 47 

Mixing Ingredients Dry ... 8 

Methods . 47 

Methods, by Hand .8, 47 

Requirements for . 46 

Moistening Lower Coat . 61 

Mortar, Tensile Strength Required. 4 

Mortars, Curb and Gutter. 13 

Natural Deposits of Sand or Gravel. 5 

Oil in Concrete . 61 

Pavements, Concrete, . 26 

Where Used . 27 

Plank Walks, Repair of. 58 

Portland Cement, How to Choose. 36 

Proportions, Curb and Gutter.15, 17 

Protection, Pavement .25, 31 

Sidewalks . 50 

of Walks, Time of.. 10 

Quantities of Material for Estimates. 64 

Radius for Curb Edges. 18 

Reinforced Sidewalks . 54 

Repairing Plank Walks . 58 

Requisites, Portland Cement. 35 

Grinding .. 36 

Hardening ...' . 37 

Time of Setting . 37 













































INDEX 


Retempering Forbidden . 

Roadways and Streets . 

Roughening Surface on Grades. 

Safe Distance to Throw Concrete. 

Sand, Amount to Use.. 

Fine, Avoidance of. 

Requirements for . 

Grading . 

Granularmetric Curve. 

Sieve Analysis of.40, 

“Set” Concrete Not to Be Used. 

Shade Trees .. 

Shop-Made Sidewalks .. 

Sidewalks, on the Farm . 

Reinforced. 

Shop-Made . 

Single-Coat Work, Sidewalks . 

Mixing . 

Proportions . 

Site of Sidewalk, Preparation of. 

Slab Markings . 

Slabs, Reinforcement of . 

Sidewalk . 

Thickness of . 

In Business Districts ... 

In Residence Districts . 

Slaughter House Floors . 

Specifications, Curb and Gutter. 

Paving . 

Bellefontaine, O. 

Mason City, la. 

Sidewalks . 

Aggregate, Coarse . 

Fine . 

Base . 

Cement . 

Forms .. 

Materials . 

Sand . 

Slabs . 

Sub-Base . 

Sub-Grade . 

Tensile Strength . 

Water . 

Wearing Surface . 

Spongy Places in Sub-Grade. 

Sprinkling, Sidewalks . 

Street Crossings .. 

Streets . 


8 

19 

10 

64 

46 

54 

38 

39 

40 

44 

54 

55 

63 

65 

55 

63 

10 

11 

11 

48 

9 

7 

7 

7 

7 

7 

61 

12 

19 

27 

27 

4 

4 

4 

7 

4 

6 

4 

4 

7 

6 

5 

4 

5 

9 

5 

50 

52 

19 



















































INDEX 


Sub-Base, Curb and Gutter. 14 

Roadways and Streets . 21 

Sidewalks .5, 6, 21, 49 

Sub-Grade, Curb and Gutter. 14 

Roadways and Streets . 21 

Sidewalks . 5 

Tamping Sub-Base .r. 56 

Tar-Sand Coating, Highways. 32 

Thickness of Walks. 9 

In Business Districts. 9 

In Residence Districts . 9 

Tools for Sidewalk Work. 50 

Tree Roots . 49 

Trees, Shade . 55 

Thickness of Walks . 9 

Troweling, Excessive, to be Avoided. 56 

Uniform Slab Sidewalks . 57 

Union Between Bottom and Top Coat. 55 

Vegetable Matter, Danger of. 4 

Voids, Mortar to Overfill. 7 

Water, Requirements for . 46 

Specifications for . 5 

Wearing Surface, Curb and Gutter. 17 

Roadways and Streets . 24 

Sidewalks . 9 

Weight of Bag of Cement. 7 





























Modern and Pro¬ 
gressive Practice 
in Sidewalk and 
Curb and Gutter 
Building 

Demands the use 
of Steel Forms 




BECAUSE 

They save nine-tenlhs of the labor of form setting. 

They eliminate the lumber bill. 

They do the work more accurately. 

They do curved work and approaches as easily as straight work. 

They can be removed while the concrete is green. 

The same forms that you lay sidewalk with can be used for curb, and curb and gutter work. 


<|The Hotchkiss System of Steel Forms is the only practical one in the market. 
<1 They have been in use three years. 

They are used by the U. S. Government, and by Cities and Contractors in 
every State in the Union and in Canada. 

We guarantee ten per cent saving on all work, and give you a fair trial of the 
forms at our risk, so that you are the judge of their efficiency. 


Write for free booklets “Sidewalk Science” and “Curb 
and Gutter Construction. ” Address 

HOTCHKISS LOCK METAL FORM CO. 

Department CC BINGHAMTON, N» Y. 























Ask the Man Who Owns 

A Crescent Continuous Mixer 


How He Likes It 

You can’t afford to mix concrete by hand when 
you can buy a Crescent Continuous Mixer for hand 
or power operation and save money on every job. 

Ask some man who owns a Crescent Mixer 
what he thinks of it. He’ll tell you that it’s a bang 
up good mixer that cuts the labor cost on sidewalk 
work. 

We have a special proposition to make to every 
man who needs a Mixer. Write for Catalog “A"” 
and we'll explain. 

RABER & LANG MFG. CO., 

820 Mill Street, KENDALLVILLE, IND. 








WAIN WRIGHT 
GALVANIZED STEEL 
CORNER BAR 


For Protecting Edges of Concrete Curbs, 
Steps, Columns, Etc. 

'• Wainwright Patents” —March 9th, 1897; November 22nd, 1898; May 5th, 1903: 
March 26th, 1907; August 29th, 1907; August 2nd, 1910. 

This bar is the main feature of the 

WAINWRIGHT STEEL-BOUND CONCRETE CURB 

THE BEST IN THE WORLD 


Over Four Million Feet s «. h .«. 300 Ci,ie ‘ 

Absolutely Non-Breakable. Cheaper Than Granite. 

THIS CURB WILL STAND HARDER 
USE and LAST TEN TIMES AS LONG 
AS PLAIN CONCRETE CURBING 

CONTRACTORS can make money by laying this Curb. 

CITY ENGINEERS can save money by specifying it. 

ARCHITECTS are invited to read pages 242-243, “ Sweet’s Innex.’ 


/ 


Handsomer than Granite and much stronger. 

Continuous in Coustruction, hence never out of line. 
Galvanized Steel Corner Bar Prevents Chipping or Breaking on Edges. 



STEEL PROTECTED CONCRETE CO 

Real Estate Trust Building, PHILADELPHIA, PA. 






































How To Use Concrete 

This is a book of practical informa¬ 
tion for the concrete man, with detailed 
instructions for building forms for 
various kinds of concrete work. Tables 
of material required, cost data, etc. 
Bound in cement-colored cloth. 

Price per copy $1. Express paid. 

Concrete Pub. Co., Detroit, Mich. 



Is a Monthly Magazine devoted to 
concrete work. Full of helpful arti¬ 
cles written in plain English. 

Issued monthly. Subscription $1 per year. 
. Sample copy 10c. 

Concrete Pub. Co., Detroit, Mich. 






















JUN 26 15111 


THE COLTRIN MIXER 

Leads Them All For Sidewalk Work 

SIZES SIZES 



No. 12 Coltrin with Automatic Proportioning' Feed 


Messrs. A. H. Dunn & Co., Kansas City, Mo., Jan. 7th, 1911. 

Kansas City, Mo. 

Gentlemen: 

We have noticed the Knickerbocker Company’s ad. in “The Concrete 
Age,” that they have mixed 3,000 sq. ft. of sidewalk concrete in eight 
hours with a gang of fourteen men. If the company wants to see what 
can be done with their No. 9 Mixer, they will have to come to Kansas City 
and watch us go. With a gang of twelve men we mixed with one machine 
and put in 3,550 sq. ft. of sidewalk 4 inches thick in exactly six hours 
and forty minutes, two men finishing the same in eight hours and thirty 
minutes. 

We think that taking man for man, there is no Mixer made that can 
or will do more or better work than your Coltrin Mixer. Every bit of 
material that goes through a Coltrin is as thoroughly mixed as it can be. 
We have two No. 9 Mixers, but neither of them are for sale. 

The Novo Engine is a dandy. We have run our Mixers all season 
without one cent of expense except for oil and gasoline. It is impossible to 
choke them down. 

Wishing you a Happy New Year, we beg to remain a friend of the 
Coltrin. 

Signed) J. W. COBLE CONCRETE CONSTRUCTION CO. 

J. W. Coble, President. 

Shipped anywhere in "United States” on 5 days trial. 

Write for 1911 Catalog'. 


THE KNICKERBOCKER; CO., : j^k. on , M ici, 

V d 









'•The Standard Brand” 


MARQUETTE 

<ihe Sidewalk Cement 

The Finest Sidewalks, Curbs, Gutters and 
Pavements in the country have been laid 
with Marquette Portland Cement. Its 
rich gray color and perfect setting qualities 
make it an ideal cement for such work. 
Marquette is made better than standard— 
it exceeds the specifications, being just as 
good as modern equipment and fifteen 
years experience can make it. 

Send for booklet on the use of Marquette 
cement. 


Cement Mfg. Co. 

One copy del. to Cat. Div. 


ling 

*'L. 


nil 5 WM 























ihe Sidewalk Cement 


The Finest Sidewalks, Curbs, Gutters and 
Pavements in the country have been laid 
with Marquette Portland Cement. Its 
rich gray color and perfect setting qualities 
make it an ideal cement for such work. 

Marquette is made better than standard— 
it exceeds the specifications, being just as 
good as modern equipment and fifteen 
years experience can make it. 


Send for booklet on the use of Marquette 
cement. 


Marquette Cement Mfg. Co. 

Marquette Building 
CHICAGO, ILL. 





















LIBRARY OF CONGRESS 


"Northweste * 020 5l3Wi 
Special Sidewalk Mixer 

Easily Moved Low Cost 
Good Capacity A Handy Outfit 


Shipped on 10 days approval 



SEND FOR CATALOG 


Northwestern Steel and Iron Works 

EAU CLAIRE, WIS. 


Manufacturers of Everything in the 
Concrete Machinery Line 











